Screw press

ABSTRACT

A screw press is provided comprising a frame, a saddle fixed relative to the frame and a slider element adapted to be driven into abutment with the saddle by operation of a screw shaft which is arranged to threadedly engage the frame and which has the slider element mounted at an end thereof. Rotation of the screw shaft to impart thereto a force driving the slider element into engagement with the saddle is effected by electric motor means which include a stator and a rotor, with the rotor being arranged as a flywheel of the press fixedly mounted upon the screw shaft. The stator is arranged to be fixed relative to the rotor and as the driving force imparted to the shaft during operation of the press causes the rotor to move in directions axially of the screw shaft, the stator is constrained to move therewith by slots formed in the frame which extend in directions parallel to the axis of the screw shaft.

United States Patent [191 Yonezawa et al.

[ 51 Oct. 22, 1974 SCREW PRESS [75] Inventors: Toshiya Yonezawa;Tadahiko Inuki,

both of Kitayshu, Japan [73] Assignee: Nippon Steel Corporation, Tokyo,

Japan [22] Filed: Dec. 29, 1972 [21] Appl. No.: 319,683

[30] Foreign Application Priority Data Dec. 28, 1971 Japan 46-471280Dec. 28, 1971 Japan 46-471281 Dec. 28, 1971 Japan 46-471279 52 us. Cl72/454, 100/289, 310/96 [51] Int. Cl B2lj 9/18 [58] Field of Search72/454; 100/289; 310/96 [56] References Cited UNITED STATES PATENTS2,997,945 8/1961 Coton 100/289 3,418,860 12/1968 Hany 3,626,222 '12/1971Dischler 310/96 FOREIGN PATENTS OR APPLICATIONS 1,300,829 8/[969 Germany72/454 Primary Examiner--C. W. Lanham Assistant ExaminerGene P. CrosbyAttorney, Agent, or Firm-Toren, McGeady and Stanger [57] ABSTRACT Ascrew press is provided comprising a frame, a saddle fixed relative tothe frame and a slider element adapted to be driven into abutment withthe saddle by operation of a screw shaft which is arranged to threadedlyengage the frame and which has the slider element mounted at an endthereof. Rotation of the screw shaft to impart thereto a force drivingthe slider element into engagement with the saddle is effected byelectric motor means which include a stator and a rotor, with the rotorbeing arranged as a flywheel of the press fixedly mounted upon the screwshaft. The stator is arranged to be fixed relative to the rotor and asthe driving force imparted to the shaft during operation of the presscauses the rotor to move in directions axially of the screw shaft, thestator is constrained to move therewith by slots formed in the framewhich extend in directions parallel to the axis of the screw shaft.

5 Claims, 5 Drawing Figures iliih t: In:

SCREW PRESS The present invention relates to a screw press used informing the material to be formed by forging.

As a forming equipment by forging the material to be formed, forexample, a fluid-pressure press such as a hydraulic press is generallyknown. Also it is well known that a screw press is used as forming byforging can be done easily with simple structure with quite lowproduction cost as compared to other types of presses.

In the drawings: FIG. l'is a view in front elevation of a conventionalFIG. 2 is a view in front elevation of a first embodiment of the presentinvention with portions cut away and partially in section;

FIG. 3 is a plan view of the embodiment of FIG. 2 with portions cut awayand partially in section;

FIG. 4 is a partial front elevation showing a modification of theembodiment of FIG. 2; and

FIG. 5 is a view in front elevation of another embodiment of the presentinvention.

An example of a conventionally known screw press will be explainedreferring to the drawings.

In FIG. 1, l is a machine frame, and a saddle 4 having a hammer part 3is provided at the base portion of the machine frame 1. A slider element5 also having a hammer part 3' is insertedly fitted with guide pieces 6provided at the inner side of the machine frame 1 in a freely slidablemanner. 7 is a flywheel insertedly attached to the upper end of a screwshaft 8 which is made to go through the upper part of the machine frameI, and the lower end of the screw shaft is insertedly positioned intothe above-mentioned slider 5 in a freely rotatable manner. And the screwshaft 8 having male screw provided thereon is insertedly fitted with afemale screw part 9 provided at the upper part of the machine frame 1 ina freely movable manner up and down (refer to FIG. 2). Friction disks 10are insertedly fitted with a driving shaft 11 in such a manner as beingpositioned near the outer side plane of the abovementioned flywheel 7. Abearing 13 is provided at the upper part of a bracket 12 provided at theupper outside of the machine frame I, and supports the driving shaft 11in a horizontal direction. A V-pulley 14 is insertedly attached to oneend of the driving shaft 11, and a V-pulley 15 is insertedly fitted tothe shaft of an electric motor, thus having V-shape belt 16 wound aroundthem. A rotating direction change over lever 17 for the abovementionedflywheel 7, has its upper end insertedly positioned at the driving shaft11, while its center part is held with a pin in place at a support piece18 provided at the bracket 12 in a freely tilting manner.

When forming by forging is done by a screw press I composed as mentionedabove, first an electric motor is started to rotate the friction, disk10 insertedly fitted with the driving shaft 11. Next the lever 17 isoperated to push the friction disk 10 for lowering the screw shaftagainst the flywheel, then the flywheel 7 is driven by the frictionpower between the friction disk 10 and the flywheel 7. Therefore, thescrew shaft 8 connected to said flywheel is rotated by the rotatingforce of the flywheel 7 to lower the slider 5 provided at the lower endof the screw-shaft, thus the material to be formed placed on the saddle4 is stricken. After striking, the change over lever 17 is quicklyoperated in a reverse direction to release the pressing of the frictiondisk 10, which is to lower the screw shaft, against the flywheel 7, thencontrary to the time of lowering, the friction disk 10, which is toelevate the screw shaft, is pushed against the above-mentioned flywheel7, making said flywheel 7 rotate in a direction reverse to that inlowering the screw shaft by friction, thus elevating the screw shaft 8.

As has been explained above in a conventional screw press large frictiondisks 10 are provided at the upper part of a press, and these frictiondisks are pushed against the flywheel of the press and rotated, torotate the screw shaft which is connected to said flywheel by drivingforce through friction, then the material to be formed is forged withthe mold provided at the lower part of the screw shaft by up and downmovement of the screw shaft 8. Also in a conventional type screw press,the driving power transmitted to the flywheel through friction disks isdetermined by the coefficint of friction of friction material such asleather, etc., placed over the contacting plane of the flywheel and bythe pushing power of the friction disk. Therefore in order to transmitlarge driving power, large pushing power and large coefficient offriction are required. However, as the pushing power becomes large, slipis caused because of the difference in speed between the friction diskand the flywheel at the time of acceleration, etc., and as great volumeof heat is generated by this slip, there is a certain limit for saidpushing power of the friction disk.

Further, since the acceleration, reduction and damping function of theflywheel are all determined by the pushing power of the friction diskand the change over control, etc. of the friction disk being pushed,very delicate adjustment is necessary, largely depending on skill byexperience of an operator, thus there are such disadvantages that theworkmanship in operation and handling largely affects the forge-formingoperation and the maintenance of the press, etc. Also as has beenexplained in the description of the set-up, the fact that large frictiondisk is rotated at high speed over the screw press constitutes big fearand risk in operational safety.

Under thecircumstances, the present invention is intended to obtain ascrew press in which the operation and control of the flywheel can bedone automatically without depending on manual operation yet securingproper control, with quite safe equipment arrangement.

Now, examples of the present invention shall be explained in detailreferring to'the drawings.

Example .1

- In FIG. 2 and FIG. 3, 1 is a machine frame, and a saddle 4 having ahammer part 3, is provided at the base part within the machine frame. Aslider element 5 also having a hammer part 3 is insertedly fitted withguide pieces 6 provided at the inner side of the abovementioned machineframe 1 in a freely slidable manner. A flywheel 7 made of conductivemetal is insertedly attached to the upper end of the screw shaft 8 whichis made to go through the upper part of the machine frame. Further, thelower end of said screw shaft 8 is insertedly provided at theabove-mentioned slider 5 in a freely rotatable manner.

The above-mentioned screw shaft 8 having male screw provided thereon isinsertedly fitted with a female screw part 9 provided at the upper partof the machine frame 1 in a freely movable manner up and down. Linearmotors l9 face against the side plane of the above-mentioned flywheel 7,and a plural number of the same are provided with certain gaps in aradial manner around the screw shaft 8. Said linear motors 19 areintegrally provided with a support frame 20 which is insertedly fittedwith the screw shaft 8 at the upper or lower portion of said flywheel 7in such manner that said screw shaft is freely rotatable. A fixed frame21 is provided at the upper part of the machine frame 1, and has guidegrooves 22 facing against each of the support frames 20 to which saidlinear motors 19 are provided and also as having the forward end partsof the support frame 20 insertedly fitted therewith in a freely slidablemanner. 23 is a checking piece such as screw cover.

Now, the function of the present invention having the above-mentionedset-up shall be explained in details. First when forming by forging isdone, as the linear motors 19 are electrified, said linear motors l9rotate the flywheel 7 to either right or left direction as shown byarrows in H6, 3. Therefore along with the rotating movement of saidflywheel 7 the screw shaft 8 being connectedly provided with saidflywheel will rotate integrally with the flywheel, and is for instancescrewed downward. At this time the support frames 20 to which linearmotors 19 are integrally provided descend along the guide grooves 22 ofthe fixed frames 21 corresponding to the descending of the screw shaft8. Further the support frames 20 will, by the insertedly fitting withthe guide grooves, hold the linear motors 19 at fixed positions withoutbeing rotated following the rotating action of the flywheel 7, alsosupporting such reaction as accompanying with the rotation of theflywheel 7. As mentioned above, the linear motors 19 will have up anddown movements commonly made together with the flywheel 7 through thesupport frame 20, thereby the motors can always secure proper positionagainst said flywheel thus insuring sure driving. Further, as the screwshaft 18 descends, the material to be formed placed on the hammer part 3of the saddle 4 is stricken by the hammer part 3' of the slider providedat the lower end of the screw shaft 8.

The control of the screw shaft descending point is done by hitting alimit switch 24 provided at'the side part of the machine frame with astriker 25 provided at the slider 5. That is, as the striker 25 hits thelimit switch 24, the phase with which current is supplied to the linearmotors 19 is changed over giving rotating force in a reverse directionto the flywheel 7, thus elevating the flywheel 7 through the screw shaft8. The upper limit of the slider 5 is detected by a limit switch 26,giving a braking force to the linear motors 19 to stop the mold at thepredetermined position. By repeating the above-mentioned actioncontinuous forging can be done.

FIG. 4 shows a modification of the above-mentioned example. Thatis thelinear motors 19 are so provided as facing against the upper plane ofthe flywheel, and when the support frame to which linear motors 19 areintegrally provided is provided under the flywheel 7, the linear motors19 are naturally so provided as facing against under plane of theflywheel. As has been explained above, the present invention has such aset-up that linear motors are used as a driving means for the flywheel,and the linear motors are made to follow the up and down movement of theflywheel along the guide grooves of the fixed frame, and said linearmotors are automatically controlled to provide smooth action of theacceleration, reduction and damping the flywheel. Therefore'the presentinvention does not call for man power as in the conventional equipment,thus delay in production, inadequate forming or troubles in drivingsystem, etc. in forge-forming operation and equipment maintenance whichaccompany with manual operation can be eliminated, and at the same timefear in operation in safety can be removed, thus it has very greateffectin improving productivity and safety.

Example 2 In FIG. 5, 201 is a machine frame, 204 is a saddle having ahammer part 203 being provided at the base part of said machine frame.205 is a slider element also having a hammer part 203' and is insertedlyfitted with guide pieces 206 provided at inner side of said machineframe 201 in a freely slidable manner. 207 is a flywheel made ofconductive metal and is insertedly attached to a screw shaft 208 whichis made to go through the upper part of the machine frame, and the lowerend of said screw shaft 208 is insertedly provided at the abovementionedslider 205 in a freely rotatable manner. The thickness of the side planeof the flywheel 207 should have at least such value as equal to or morethan the up and down movement distance of the screw shaft 208. Theabove-mentioned screw shaft 208 having male screw provided thereon isinsertedly fitted with a female screw part 209 provided at the upperpart of the machine frame in a freely movable manner up and down. 219are linear motors and plural number of the same are provided withcertain gaps facing against the side plane of the above-mentionedflywheel 207 in a radial manner around the screw shaft 208. 220 is afixed frame provided at the upper part of the machine frame 1, and theabove-mentioned linear motors 219 are fixedly provided at the fixedframe in such manner that the motors 219 are always positioned withinthe up and down movement range of the above-mentioned flywheel.

The function of the above example having such set up as mentioned aboveshall be explained in detail.

First when forge-forming is done, as the linear motors 219 areelectrified, the linear motors 219 rotate the flywheel 207 either toright or left direction. Therefore, the screw shaft 208 connectedlyprovided with the flywheel 207 rotates integrally with the flywheel 207along the rotating movement of the flywheel 207, thus screwed downward.As mentioned above even when the flywheel 207 is gradually descended thelinear motors 219 are fixedly provided at the fixed frame 220 within theup and down movement range of the flywheel 207, therefore the motors arealways facing against the side plane of the flywheel 207, thus theflywheel 207 can be continuously driven. Further, as the screw shaft 208descends, the material to be formed placed on the hammer part 203 on thesaddle 204 is stricken by the hammer part 203 of the slider 205 providedat the lower end of the screw shaft 208.

The control of the descending point of the screw shaft is done byhitting a limit switch 221 provided at the side of the machine framewith a striker 222 provided at the slider 205. That is, as the striker222 hits the limit switch 221, the phase with which current is suppliedto the linear motors 219 is changed over, giving rotating force toreverse direction to the flywheel 207 elevating the flywheel 207 throughthe screw shaft 208. The upper limit of the slider 205 is detected byanother limit switch 223, giving braking froce to the linear motor 219stopping the same at a predetermined position. By repeating theabove-mentioned action continuous forging can be done.

As described above, in the present example such a flywheel is providedas having the thickness of side plane at least corresponding to the upand down movement distance of the screw shaft, and linear motors areprovided at a fixed frame as a driving device for the flywheel in such amanner as being positioned within the range of up and down movement ofthe abovementioned flywheel, thereby said linear motors are made alwaysto face against the flywheel regardless the up and down movement of theflywheel, and are automatically controlled, further the press has sucharrangement and set up that the acceleration, reduction and dampingfunction of the flywheel can be done smoothly, thereby same effect as inExample 1 can be obtained.

While specific embodiments of the invention have been shown anddescribed in detail to illustrate the application of the inventiveprinciples, it will be understood that the invention may be embodiedotherwise without departing from such principles.

We claim:

1. A screw press comprising, in combination, a frame, a saddle fixedlymounted relative to said frame, a slider element adapted to be driveninto abutment with said saddle, a screw shaft rotatable about a fixedaxis and having said slider element operatively connected thereto, saidshaft being threadedly engaged upon said frame to impart a driving forceto said slider element upon rotation of said shaft about said axis,electrical motor means including a stator and a rotor connected toproduce a driving force for said press,

said rotor being arranged as a flywheel of said press and being fixedlymounted upon said screw shaft to rotate therewith, and means mountingsaid stator for movement relative to said frame in directions parallelto said axis but constraining said stator to prevent rotative movementthereof about said axis, whereby said stator and said rotor movetogether in a fixed relationship relative to each other in directionsparallel to said axis during rotation of said shaft.

2. A press according to claim 1 wherein said mounting means comprise asupport element having said stator fixedly mounted thereupon andextending between said screw shaft and said frame, means freelyrotatively connecting said support element to said screw shaft butpreventing relative axial motion therebetween, slot means formed in saidframe extending parallel to said axis, and slot engaging means formed onsaid support element and arranged for sliding engagement with said slotmeans.

3. A press according to claim 1 wherein said rotor comprises a generallydisc-shaped configuration having an outer peripheral surface and whereinsaid stator is located adjacent said peripheral surface and spacedradially therefrom to provide an interspacing clearance therebetween.

4. A press according to claim 1 wherein said rotor comprises a generallydisc-shaped configuration having a planar surface arrangedperpendicularly to said axis and extending radially therefrom, andwherein said stator is located adjacent said planar surface and spacedtherefrom axially of said screw shaft to provide an interspacingclearance therebetween.

5. A press according to claim 1 wherein said stator comprises aplurality of segmental stator elements arranged symmetrically relativeto said rotor about said axis.

1. A screw press comprising, in combination, a frame, a saddle fixedlymounted relative to said frame, a slider element adapted to be driveninto abutment with said saddle, a screw shaft rotatable about a fixedaxis and having said slider element operatively connected thereto, saidshaft being threadedly engaged upon said frame to impart a driving forceto said slider element upon rotation of said shaft about said axis,electrical motor means including a stator and a rotor connected toproduce a driving force for said press, said rotor being arranged as aflywheel of said press and being fixedly mounted upon said screw shaftto rotate therewith, and means mounting said stator for movementrelative to said frame in directions parallel to said axis butconstraining said stator to prevent rotative movement thereof about saidaxis, whereby said stator and said rotor move together in a fixedrelationship relative to each other in directions parallel to said axisduring rotation of said shaft.
 2. A press according to claim 1 whereinsaid mounting means comprise a support element having said statorfixedly mounted thereupon and extending between said screw shaft andsaid frame, means freely rotatively connecting said support element tosaid screw shaft but preventing relative axial motion therebetween, slotmeans formed in said frame extending parallel to said axis, and slotengaging means formed on said support element and arranged for slidingengagement with said slot means.
 3. A press according to claim 1 whereinsaid rotor comprises a generally disc-shaped configuration having anouter peripheral surface and wherein said stator is located adjacentsaid peripheral surface and spaced radially therefrom to provide aninterspacing clearance therebetween.
 4. A press according to claim 1wherein said rotor comprises a generally disc-shaped configurationhaving a planar surface arranged perpendicularly to said axis andextending radially therefrom, and wherein said stator is locatedadjacent said planar surface and spaced therefrom axially of said screwshaft to provide an interspacing clearance therebetween.
 5. A pressaccording to claim 1 wherein said stator comprises a plurality ofsegmental stator elements arranged symmetrically relative to said rotorabout said axis.